Method for detecting a response of each probe zone on a test strip

ABSTRACT

A method for detecting a response of each probe zone on a test strip is provided. The present method includes providing a test strip having a color pattern displayed thereon. The color pattern occurs in response to a tested solution contacting with the test strip and including a plurality of color lines displayed in sequence from a bottom portion of the test strip to a top portion thereof. The site of each color line represents a probe zone of the test strip. Capturing a whole image of the test strip and selecting at least one scan line perpendicular to the image of the color lines therefrom. Setting a pixel position of the scan line having a minimum pixel value corresponding to a bottom edge of the test strip and using the pixel position as a reference to identify respective pixel positions of the color lines on the scan line so as to identify the image positions thereof on the whole image. A response of each probe zone of the test strip related to a gray level of a corresponding image position is thus obtained.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for detecting aresponse of each probe zone on a test strip, and more particularly to amethod for detecting a response of each probe zone on a test strip viaan image capturing technology.

[0003] 2. Description of the Prior Art

[0004] Over the past decade, there has been an increased need and demandfor analysis of various biological specimens, for purposes ranging frompregnancy testing to drug analysis. Considerable time and effort hasbeen expended by way of devising systems and analytic techniques toensure reliable testing and accurate results.

[0005] Moreover, with increasing rise in the use of abuse-type drugs,the need for detecting and identifying those drugs and their metabolitesis becoming more important. With this need, many more tests are requiredto monitor the use of abuse-type drugs.

[0006] Thin layer chromatography (TLC) screening procedures fordetecting drugs in urine require the careful preparation of a testspecimen and then a skillful application of that test specimen to aplate placed into a developing chamber. Once the plate is removed fromthe chamber and dried, it is sprayed with visualization reagents.Location and color of spots are compared with those of known standards.Qualitative judgements are made as to the presence of various drugs inthe unknown sample. The procedure is tedious, time consuming andrequires skilled personnel to interpret the results.

[0007] The EMIT (Enzyme Multiplied Immuno-chemical Test) procedure is asemi-quantitative immuno-assay for drugs of abuse in biological fluids.The laboratory test requires trained technicians to perform and theequipment necessarily costs several thousands of dollars.

[0008] The RIA (Radio-Immuno-Assay) procedure is a sensitive andquantitative laboratory procedure for detecting drugs of abuse. Thevarious immunochemicals are labeled with radioactive compounds andrequire special care in their use and disposal. A license is requiredfrom the government to use this laboratory procedure because of thepresence of radioactive materials. The GLC (Gas-Liquid Chromatography)procedure can provide the highest degree of accuracy in drug analysis.However, the necessary equipment is expensive and the procedure iscomplicated. Consequently, highly trained personnel are required for itsuse.

[0009] Each of these well-known procedures requires skilled techniciansand relatively sophisticated equipment. Consequently, the testingprocedure is necessarily expensive.

[0010] However, the increase of drug abuse has increased a need for newmethods of analyzing drug residues in physiological fluid. A drug abusetest paper for testing the presence or absence of drugs in a fluidspecimen collected from a test subject is developed. The drug abuse testpaper is prepared in accordance with unique procedure whereby pHinsensitivity and color change sensitivities to tested fluids areobtained. The color change of the drug abuse test paper sensitive to onespecific substance present in the fluid specimen collected from the testsubject applied on the drug abuse test paper is simply verified byvisual judgement. This abuse-type drug testing is rapid and convenient.However, it is not convincing for concluding the test subject has usedabuse-type drugs.

[0011] Accordingly, it is an intention to provide means capable ofdetecting and identifying the presence or absence of drugs of abuse in afluid specimen, which can overcome the problems of the conventionalmethods.

SUMMARY OF THE INVENTION

[0012] It is one objective of the present invention to provide a methodfor detecting a response of each probe zone on a test strip, whichcaptures a whole image of the test strip and using the image position ofa bottom edge of the test strip as a reference to identify the imagepositions of the responses of the probe zones of the test strip. Theresponses of the probe zones of the test strip thus can be accuratelyand rapidly determined in accordance with the gray levels of the relatedimage positions.

[0013] It is another objective of the present invention to provide amethod for detecting a response of each probe zone on a test strip,which can be used as an implement to detect or identify the presence orabsence of drugs of abuse in a test sample.

[0014] It is still another objective of the present invention to providea method for detecting a response of each probe zone on a test strip,which is quick and convenient to use by non-sophisticated personnel innon-laboratory settings, and performs assays for multiple drugs of abusesimultaneously.

[0015] It is a further objective of the present invention to provide amethod for detecting a response of each probe zone on a test strip,which associates with an image capturing/processing technology toanalyze drug residues in physiological fluid to attain the purposes ofaccuracy, rapid and cost effective in drug abuse detection technology.

[0016] In order to achieve the above objectives of this invention, thepresent invention provides a method for detecting a response for eachprobe zone on a test strip. The present method includes providing a teststrip having a light color base and a color pattern displayed thereon.The color pattern occurs in response to a tested solution contactingwith the test strip and including a plurality of color lines displayedin sequence from a bottom portion of the test strip to a top portionthereof. The site of each color line represents a probe zone of the teststrip. Capturing a whole image of the test strip and selecting at leastone scan line perpendicular to the image of the color lines from thewhole image. Setting a pixel position of the scan line having a minimumpixel value corresponding to the image of a bottom edge of the teststrip. And, assigning respective pixel positions of the scan linecorresponding to each of the color lines of the test strip by using thepixel position with the minimum pixel value as a reference and inaccordance with the sequence of the color lines displayed on the teststrip. Thereby, a response of each probe zone of the test strip relatedto a respective pixel value of the pixel position corresponding to thecolor line of the probe zone is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The objectives and features of the present invention as well asadvantages thereof will become apparent from the following detaileddescription, considered in conjunction with the accompanying drawings.

[0018]FIG. 1A to FIG. 1D shows schematic top views of a drug abuse teststrip under various testing situations of the present invention;

[0019]FIG. 2A is a schematic perspective view of a drug abuse test stripafter testing a sample fluid of the present invention;

[0020]FIG. 2B is a schematic top view of the drug abuse test strip ofFIG. 2A; and

[0021]FIG. 3 is a diagram of pixel value verse pixel positionestablished in accordance with one scan line selected from a whole imagecaptured from the drug abuse test strip of FIG. 2B.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] From a view of broad application, the present invention providesa method for detecting a response for each probe zone on a test stripafter testing a sample solution, which associates with an imagecapturing/processing technology to detect respective responses of theprobe zones on the test strip to qualitatively and quantitativelyidentify specific substances in the sample solution. More specifically,the present invention utilizes the image capturing technology to capturethe whole image of a test strip having a color pattern displayedthereon. The color pattern includes a plurality of color lines each ofwhich representing a probe zone of the test strip having a color changein response to a specific substance in the sample solution. Inaccordance with the image of the color pattern of the test strip, theresponse of each probe zone of the test strip to the sample solution canbe determined so as to detect the presence or absence of the specificsubstance related to in the sample solution. The present method issuitable to be used as a drug abuse detection technology. That is, thepresent method can be used to detect the response for each probe zone ona drug abuse test strip after testing a physiological fluid, such as aurine specimen fluid, collected from a test subject, instead of visualjudgment of the responses of the probe zones on the drug abuse teststrip.

[0023] The present method will be described in detail with a drug abusetest strip as an example in the following. However, before detaileddescription of the present method, an introduction of various colorpatterns occurring on one drug abuse test strip under various testingsituations is provided herein. Firstly, referring to FIG. 1A, which is aschematic top view of a drug abuse test strip 10 prior to testing asample fluid collected from a test subject. The drug abuse test strip 10is blank and no color pattern displayed thereon prior to testing thesample fluid. The dotted lines 11 through 16 respectively represent aprobe zone of the drug abuse test strip 10. The top probe zone of thedrug abuse test strip 10 corresponding to the site of dotted line 11displays color change in response to the sample fluid, which is used toindicate whether the amount of the sample fluid is sufficient to movethrough all probe zones of the drug abuse test strip 10 by capillaryaction. The other probe zones of the drug abuse test strip 10corresponding to the sites of dotted lines 12 through 16 respectivelydisplay color change in response to a respective abuse-type drugpresenting in the sample fluid. It should be noted the drug abuse teststrip used in the present invention is not limited to the kind of thedrug abuse test strip 10 of FIG. 1A.

[0024] Referring to FIG. 1B, which shows a color pattern of the drugabuse test strip 10 having no color change occurring in the top probezone represented by the dotted line 11, which is under a testingsituation that the amount of the sample fluid is not sufficient toassure the sample fluid moves through all probe zones of the drug abusetest strip 10. Therefore, in accordance with the color patternconsisting of solid lines 14 through 16 shown in FIG. 1B, the drugs ofabuse presenting in the sample fluid cannot completely detected andidentified. Referring to FIG. 1C, which shows a color pattern of thedrug abuse test strip 10 having only one color line 11 displayed in thetop probe zone of the drug abuse test strip 10, which means all otherprobe zones represented by the dotted lines 12 through 16 have positiveresponses to the sample fluid, and all drugs of abuse corresponding tothese probe zones present in the sample fluid. Referring to FIG. 1D,which shows a color pattern of the drug abuse test strip having colorlines 11, 12 and 15 displayed in the top probe zone and some other probezones of the drug abuse test strip 10, which means the top probe zone 11has a positive response to the sample fluid, indicating the amount ofthe sample fluid is sufficient, and the probe zones represented by thecolor lines 12 and 15 have a negative response to the sample fluid,indicating that the absence of the drugs of abuse corresponding to thesetwo probe zones in the sample fluid. On the contrary, the probe zonesrepresented by the dotted lines 13, 14 and 16 have a positive responseto the sample fluid, indicating that the presence of the drugs of abusecorresponding to these three probe zones in the sample fluid.

[0025] The present invention associates with the imagecapturing/processing technology to detect responses for the respectiveprobe zones of the drug abuse test strip 10. The color pattern includingvarious color lines displayed on the drug abuse test strip 10 aftertesting the sample fluid is captured and analyzed to identify the drugsof abuse present in the sample fluid. Referring to FIG. 1B to FIG. 1D,there are some testing situations happen. One first testing situation isthe color line 11 is not displayed due to an insufficient amount of thesample fluid, see FIG. 1B. One second testing situation is only thecolor line 11 displayed, while other color lines 12 through 16 not,which indicates that all the probe zones of the drug abuse test strip 10have a positive response to the sample fluid. Thus, all the drugs ofabuse corresponding to all the probe zones present in the sample fluid,as shown in FIG. 1C. One third testing situation is the color line 11and some other color lines 12 and 15 displayed, which indicates theprobe zones of the color lines 12 and 15 have a negative response to thesample fluid. The drugs of abuse related to absent in the sample fluid.In view of the test results under the various testing situations, theimage information of the respective color lines 12 through 16 can not beidentified with the color line 11 as a reference.

[0026] Hence, the present invention provides a method to identify theimage information of the respective color lines 11 through 16 of thedrug abuse test strip 10 under the various testing situations. Referringto FIG. 2A, the drug abuse test strip 10 having a light color base, suchas white base, and a color pattern displayed thereon, is provided. Thecolor pattern includes color lines 11 through 16 displayed in sequencefrom the top portion of the drug abuse test strip 10 to the bottomportion thereof. The color lines 11 through 16 have the same color,while different shades. The site of each of the color lines 11 through16 represents a probe zone of the drug abuse test strip 10. Except forthe top probe zone represented by the color line 11, the probe zone hasa positive response to the sample fluid, the site of the probe zonewould display a light shade color line, even does not display the colorline. That indicates the presence of the drug of abuse to be detectedpresents in the sample fluid. On the contrary, when the probe zone has anegative response to the sample fluid, the site of the probe zone woulddisplay a dark shade color line, indicating the absence of the drug ofabuse to be detected in the sample fluid. In the present invention, theshade of the color line is inversely proportional to the concentrationof the detected drug of abuse in the sample fluid. The whole image ofthe drug abuse test strip 10 is then captured by an image capturingdevice, such as a scanner associated with a charge-coupled device (CCD).Referring to FIG. 2B, selecting at least one scan line L-L′ from thewhole image. The scan line L-L′ is perpendicular to the image of thecolor lines 11 through 16. A diagram of pixel value verse pixel positionfor the whole image of the drug abuse test strip 10 is established inaccordance with the scan line L-L′, as shown in FIG. 3. The diagram ofFIG. 3 shows three curves respectively representing the relationship ofpixel value and pixel position for red (R), green (G), blue (B) channelsof the charge-coupled device. The R, G, B channels are disposed on thecharge-coupled device in parallel, and each of the R, G, B channelsincluding a plurality of sensor cells, and each sensor cellcorresponding to a pixel position. Alternately, the present inventioncan utilize a charge-coupled device with a single channel, such as acharge-coupled device with a red channel, a charge-coupled device with agreen channel or a charge-coupled device with a blue channel, to capturethe whole image of the drug abuse test strip 10. A shade would appear onthe bottom edge of the drug abuse test strip 10 due to thethree-dimensional structure of the drug abuse test strip 10. The shadeof the bottom edge of the drug abuse test strip 10 would correspond toan image position having a minimum gray level, i.e. minimum pixel value,on the whole image of the drug abuse test strip 10. Thus, referring toFIG. 3, setting a pixel position of the scan line L-L′ having a minimumpixel value, the position between pixel positions 301 and 326,corresponding to the image of the bottom edge of the drug abuse teststrip 10. As shown in FIG. 3, the R pixel values of the whole image ofthe drug abuse test strip 10 show significant differences. It ispreferable that the pixel position corresponding to the bottom edge ofthe drug abuse test strip 10 is determined depending on the minimum Rpixel value. Then, using the pixel position having the minimum pixelvalue as a reference, i.e. designating the position between pixelpositions 301 and 326 corresponding to the bottom edge of the drug abusetest strip 10, and in accordance with the sequence of the color lines 11through 16 displayed on the drug abuse test strip 10, to assignrespective pixel positions of the scan line L-L′ corresponding to eachof the color lines 11 through 16 of the drug abuse test strip 10.Thereby, the response of each probe zone of the drug abuse test strip 10to the sample fluid is determined in accordance with the respectivepixel value corresponding to the probe zone. The concentration of thedetected drug of abuse present in the sample fluid also can be obtainedbased on the response thereof.

[0027] The present method can be automatically performed by anapplication installed in a computer associated with an image capturingdevice. The present method is suitable to be used as means to accuratelyand rapidly detect or identify the presence or absence of drugs of abusein the sample fluid. And, the present method does not need an expensiveequipment and a sophisticated personnel to perform. Thus, the presentinvention provides an extremely important advance in the drug abusedetection technology. Thousands of tests will no longer have to beconducted using the more sophisticated TLC, EMIT, RIA and GLCprocedures.

[0028] The embodiments are only used to illustrate the presentinvention, not intended to limit the scope thereof. Many modificationsof the embodiments can be made without departing from the spirit of thepresent invention.

What is claimed is:
 1. A method for detecting a response for each probezone on a test strip, comprising: providing a test strip having a lightcolor base and a color pattern displayed thereon, said color patternoccurring in response to a tested solution contacting with said teststrip and including a plurality of color lines displayed in sequencefrom a bottom portion of said test strip to a top portion thereof, thesite of each said color line representing a probe zone of said teststrip; capturing a whole image of said test strip; selecting at leastone scan line from the whole image, said scan line being perpendicularto the image of said color lines; setting a pixel position of said scanline having a minimum pixel value corresponding to the image of a bottomedge of said test strip; and assigning respective pixel positions ofsaid scan line corresponding to each of said color lines of said teststrip by using said pixel position with the minimum pixel value as areference and in accordance with the sequence of said color linesdisplayed on said test strip, thereby a response of each probe zone ofsaid test strip related to a respective pixel value of one said pixelposition corresponding to one said color line is obtained.
 2. The methodof claim 1, wherein the pixel position of said scan line having aminimum red pixel value is set to correspond to the image of the bottomedge of said test strip.
 3. The method of claim 1, wherein the pixelposition of said scan line having a minimum average pixel value formedof red, green, blue pixel values is set to correspond to the image ofthe bottom edge of said test strip.
 4. The method of claim 1, whereinsaid test strip has a white base.
 5. The method of claim 1, wherein saidtest strip is a kind of drug abuse test paper having a plurality ofprobe zones, wherein one top probe zone has a color change in responseto said tested solution and the other probe zones respectively have acolor change in response to a specific drug of abuse in said testedsolution.
 6. The method of claim 5, wherein said tested solutionincludes a biological fluid collected from a subject.
 7. The method ofclaim 6, wherein said biological fluid includes a urine specimen fluid.8. The method of claim 1, wherein the whole image of said test strip iscaptured by a scanner associated with a charge-coupled device.
 9. Amethod for selecting a reference to identify an image of a response ofeach probe zone on a test strip, comprising: providing a test striphaving a light color base and a color pattern displayed thereon, saidcolor pattern occurring in response to a tested solution contacting withsaid test strip and including a plurality of color lines displayed insequence from a bottom portion of said test strip to a top portionthereof, the site of each said color line representing a probe zone ofsaid test strip; capturing a whole image of said test strip; selectingat least one scan line from the whole image, said scan line beingperpendicular to the image of said color lines; and setting a pixelposition of said scan line having a minimum pixel value corresponding tothe image of a bottom edge of said test strip and using said pixelposition corresponding to the bottom edge of said test strip as areference to identify respective pixel positions of said color lines ofsaid test strip on said scan line so as to identify the image positionsthereof on the whole image.
 10. The method of claim 9, wherein the pixelposition of said scan line having a minimum red pixel value is set tocorrespond to the image of the bottom edge of said test strip.
 11. Themethod of claim 9, wherein the pixel position of said scan line having aminimum average pixel value formed of red, green, blue pixel values isset to correspond to the image of the bottom edge of said test strip.12. The method of claim 9, wherein said test strip has a white base. 13.The method of claim 9, wherein said test strip is a kind of drug abusetest paper having a plurality of probe zones, wherein one top probe zonehas a color change in response to said tested solution and the otherprobe zones respectively have a color change in response to a specificdrug of abuse in said tested solution.
 14. The method of claim 13,wherein said tested solution includes a biological fluid collected froma subject.
 15. The method of claim 14, wherein said biological fluidincludes a urine specimen fluid.
 16. The method of claim 9, wherein thewhole image of said test strip is captured by a scanner associated witha charge-coupled device.